i) Path variables work properly. Whenever <thing>: prefixes a path the relevant path variable will be used (<thing>$Path). Paths in path variables will be resolved in the same way. The following new errors may occur:
Object type Meaning
0 Not present
1 File
2 Directory
3 File and Directory - this means this file has been
identified as a MultiFS file, and hence can be treated as a
directory too. Objects of this type may be treated as both
files and directories.
An alternative way to think of the object type is as a bit field:
Bit Meaning when set 0 Object may have file-like operations done to it 1 Object may have directory-like operations done to it
iv) Given a filename, FileSwitch can be asked to process it to produce a
mostly canonical form (mostly in the sense that the case may be different,
and wildcards may not be sorted out if the wildcarded object doesn't
exist!). So
On entry
r0 = 37
r1 = Pointer to path to be canonicalised
r2 = Pointer to buffer to be filled in
r3 = Pointer to system variable name of path to use, or 0 if none
r4 = Pointer to default path to use if no system variable is specified
or if that variable doesn't exist, or 0 if no path is the default
r5 = Buffer length
On exit
Buffer filled in with 0-terminated canonicalised name, and
r5 = number of spare bytes in the buffer after and including
the 0 terminator. If the buffer would have overflowed,
then this will be taken to negative the overflow, but
the overflow won't actually have happened. This
provides a machanism for finding out how much buffer
is needed.
This may be used as a two-pass process:
Pass 1:
In:
r0 = 37
r1 = Pointer to path
r2 = 0
r5 = 0
Out:
r5 = -(length of canonicalised path)
Pass 2:
r0 = 37
r1 = Pointer to path
r2 = Pointer to claimed buffer
r5 = size of claimed buffer
Out:
r5 should be 0, but check to make sure!
v) Given a file handle, fileswitch will return the name of the file.
OS_Args 7 (OSArgs_ReadPath)
On entry
r0 = 7
r1 = file handle
r2 = Pointer to buffer to be filled in
r5 = Buffer length
On exit
Buffer filled in with 0-terminated canonicalised name, and
r5 = number of spare bytes in the buffer after the 0 terminator.
If the buffer would have overflowed, then this will be
taken to negative the overflow, but the overflow won't
actually have happened. This provides a machanism for
finding out how much buffer is needed.
This call can be used in the same way as OS_FSControl 37.
vi) FileSwitch now processes the conversion of file info into filetype information.
OS_FSControl 38 (FSControl_InfoToFileType)
On entry
r0 = 38
r1 = a pointer to the object's name
r2 = object's load address
r3 = object's execute address
r4 = object's length
r5 = objects's attributes
r6 = object's type (file/directory)
On exit
r2 = object's type:
Special values:
-1 untyped
&1000 directory
&2000 application directory (directory whose name starts with a '!').
OS_File 20-23 (OSFile_ReadWithType, _ReadWithTypePath, _ReadWithTypePathVar
and _ReadWithTypeNoPath)
On Entry
r0 = 20, 21, 22 or 23
r1 = Pointer to name of object
On exit
r0 = object's type
r1 unchanged
r2 = Object's load address or top word of date stamp
r3 = Object's execute address or bottom word of date stamp
r4 = Object's length
r5 = object's attributes
r6 = Object's type:
Special values:
-1 untyped (r2, r3 are load and execute address)
&1000 directory
&2000 application directory (directory whose name starts with a '!').
OS_GBPB 12 (OSGBPB_ReadDirEntriesFileType)
On entry
r0 = 12
r1 = pointer to directory name
r2 = start address of data in memory (word aligned)
r3 = number of names to read from directory
r4 = offset of first item to read from directory (0 for start)
r5 = buffer length
r6 = Pointer to (Wildcarded) name to match
On exit
r0-r2 unchanged
r3 = number of objects read
r4 = offset of next item to read
r5, r6 unchanged
This call is similar in function to OS_GBPB 10, except the buffer is filled in with entries like this:
Offset Contents
0 Load address or high word of date stamp 4 Execute address of low word of date stamp 8 Length 12 File attributes 16 Object type 20 Object's file type (as for OS_File 20-23) 24 Object's name (null terminated)